Initial commit

Assets/Scripts/SolarSystem.cs

@@ -0,0 +1,54 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public class SolarSystem : MonoBehaviour
+{
+    [SerializeField] private float G = 100f;
+    private GameObject[] celestials;
+    void Start()
+    {
+        celestials = GameObject.FindGameObjectsWithTag("Celestial");
+        InitialVelocity();
+    }
+    private void FixedUpdate()
+    {
+        Gravity();
+    }
+    void Gravity()
+    {
+        foreach (GameObject a in celestials)
+        {
+            foreach (GameObject b in celestials)
+            {
+                if (!a.Equals(b))
+                {
+                    float m1 = a.GetComponent<Rigidbody>().mass;
+                    float m2 = b.GetComponent<Rigidbody>().mass;
+                    float r = Vector3.Distance(a.transform.position, b.transform.position);
+                    a.GetComponent<Rigidbody>().AddForce(
+                        (b.transform.position - a.transform.position).normalized *
+                        (G * (m1 * m2) / (r * r))
+                    );
+                }
+            }
+        }
+    }
+    void InitialVelocity()
+    {
+        foreach (GameObject a in celestials)
+        {
+            foreach (GameObject b in celestials)
+            {
+                if (!a.Equals(b))
+                {
+                    float m2 = b.GetComponent<Rigidbody>().mass;
+                    float r = Vector3.Distance(a.transform.position, b.transform.position);
+                    a.transform.LookAt(b.transform);
+                    a.GetComponent<Rigidbody>().velocity +=
+                        a.transform.right * Mathf.Sqrt((G * m2) / r);
+                }
+            }
+        }
+    }
+}